US4706144A - Rotary head device with fluid bearing - Google Patents

Rotary head device with fluid bearing Download PDF

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Publication number
US4706144A
US4706144A US06/619,147 US61914784A US4706144A US 4706144 A US4706144 A US 4706144A US 61914784 A US61914784 A US 61914784A US 4706144 A US4706144 A US 4706144A
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US
United States
Prior art keywords
support means
rotatable shaft
pattern
rotatable
rotary transformer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/619,147
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English (en)
Inventor
Takafumi Asada
Cyuryo Yoshida
Tadao Shioyama
Yoshiteru Hosokawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ASADA, TAKAFUMI, HOSOKAWA, YOSHITERU, SHIOYAMA, TADAO, YOSHIDA, CYURYO
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Publication of US4706144A publication Critical patent/US4706144A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head
    • G11B5/53—Disposition or mounting of heads on rotating support

Definitions

  • the present invention relates to a rotary head device using a dynamic pressure type fluid bearing for use in video tape recorders (hereinafter abbreviated to VTR) and provides a rotary head device which is compact and excellent in rotary performance.
  • VTR video tape recorders
  • a fixed shaft 2 is pressed in and secured in place at the central portion of a lower cylinder 1
  • a sleeve 3 is rotatably mounted on the fixed shaft 2
  • a thrust bearing seat 4 is screwed on the top of the fixed shaft 2
  • a thrust bearing 5 is screwed on the upper end of the sleeve 3.
  • Herringbone shape patterns of grooves 6A and 6B are formed on the fixed shaft 2 and a spiral groove 7 are formed on the lower surface of the thrust bearing 5 by etching, etc.
  • the space inside the bearing chamber formed between the shaft 2 and the sleeve 3 contains lubricant 8, which is oil or grease, etc., thereby comprising a dynamic pressure type fluid bearing.
  • a rotary magnetic head 10 is mounted on an upper cylinder, which is mounted on the sleeve 3. Also mounted on the sleeve 3 is a disc shape rotary transformer 11 on the rotary side of the rotary head device for transmitting to the stationary side an electrical signal extracted from a magnetic tape through the magnetic head 10, not shown in the drawings.
  • An armature magnet 13 is supported on a magnet case 14 of a motor attached to a lower end of the sleeve 3, which together with the parts mentioned above comprise a rotary side unit 20.
  • a disc shape rotary transformer 12 on the stationary side of the rotary head device which receives the aforementioned electric signal.
  • a motor stator 19 consisting of an iron plate 18, a printed substrate 17 and a coil 16.
  • the rotary unit 20 begins turning, producing a pressure by a pumping action of the patterns of grooves 6A, 6B and 7; then, the unit is floated up by the rising rigidity of the oil film, thereby enabling rotation of the rotary side unit 20 without making contact with the stationary side unit.
  • the force of the armature magnet 13 to attract the iron plate 18 and the dead weight of the rotary side unit is exerted in the direction of B, as shown in FIG. 1, while a force opposing them is produced in the direction A due to the pumping action of the spiral groove 7.
  • the dimension in the axial direction is large, thus detracting from compactness of the device.
  • the fixed shaft 2 tends to be warped due to the dead weight of the rotary unit and the side pressure by a magnetic tape 60, causing a large shift in the relative position between the magnetic head 10 and the magnetic tape 60.
  • the picture recorded by the VTR cannot be reproduced.
  • the structure was determined to be unacceptable in its performance as a portable VTR.
  • the present invention resides in a rotary head device using a dynamic pressure type fluid bearing having a lower cylinder, a rotary shaft which rotates in a sleeve placed at the center of the lower cylinder, an upper cylinder mounted on one end of the rotary shaft and having a head, a motor installed on the other end of the rotary shaft, with herringbone groove patterns formed on either one of the rotary shaft or the inner surface of the sleeve, the axial length of the herringbone groove pattern being larger on the upper cylinder side, but smaller on the motor side, said device including a pair of cylindrical rotary side and a pair of stationary side cylindrical rotary transformers.
  • FIG. 1 is a sectional view of a conventional fluid bearing cylinder
  • FIG. 2 is a sectional view of a the principal part of the same in its horizontal posture
  • FIG. 3 is a sectional view of an embodiment of this invention.
  • FIG. 4 is a sectional view of the principal part of the fluid bearing cylinder device of the present invention in its horizontal posture.
  • FIG. 3 is a sectional view of a fluid bearing cylinder device embodying this invention.
  • 21 denotes a stationary support means comprising a lower cylinder, which has a sleeve 21A at its center.
  • Numeral 22 designates a rotary shaft fixed to a disc 23 and turning in the sleeve 21A; 24 denotes a thrust bearing member fixed on the bottom surface of the rotary shaft at a right angle thereto; 26A and 26B denote herringbone patterns of grooves, which are 5 ⁇ 20 microns (hereinafter represented by ⁇ m) formed by etching or machining; 27 denotes a spiral groove formed on the thrust bearing member; and a lubricant having a viscosity of about 20 centipoises and relatively excellent in temperature characteristics is provided in the patterns of grooves 26A, 26B and the spiral groove 27, whereby a dynamic pressure type fluid bearing is composed.
  • Numeral 29 denotes a rotatable support means comprising an upper cylinder screwed onto the disc 23, which has a magnetic head 30.
  • Reference codes 31A and 31B denote a pair of coaxial rotary side cylindrical rotary transformers mounted on the disc 23; and 32A and 32B denote a pair of coaxial stationary side cylindrical rotary transformers mounted on disc 32C; 31A, 31B and 32A, 32B being paired to transmit to the stationary side the electric signal extracted from the magnetic tape by means of the rotary magnetic head 30.
  • Numeral 24 denotes a thrust bearing member which has a groove 27 and which is mounted on an end of the rotary shaft 22; 35 denotes a motor rotor mounted on the lower end of the rotary shaft 22 by means of the thrust bearing 24; and 38 denotes a motor stator mounted on the lower cylinder 21.
  • Numeral 25 designates a hard surface layer on the sleeve 21A.
  • a rotary unit 40 thus comprises disc 23, rotary transformers 31A, 31B, and magnetic head 30.
  • the rotary transformers 31A, 31B and 32A, 32B are described.
  • the rotary head device is required to be compact and thin for it to be portable.
  • Conventional rotary transformers 11 and 12 shown in FIG. 1 are in disc shapes. At least two such discs, each 2 ⁇ 2.5 milimeters thick, are necessary and their thickness occupies approximately 10 ⁇ 20 percent of the total thickness of the rotary head device.
  • the dimension of the rotary head device as a whole can be made thin by making the transformers cylindrical in shape, as shown in FIG. 3.
  • rotary transformers having a number of annular channels, for receiving coil windings as is well known in the art, (corresponding to the number of grooves on the rotary transformer in terms of its configuration) equal to the number of magnetic heads 30 mounted thereon are required; generally 2 ⁇ 5 channels are necessary.
  • two types of rotary transformers 31A and 31B differing in number of channels, such as 3 channels and 2 channels, respectively, are coaxially mounted and through a combination of these two types of transformers, rotary head devices differing in specifications, for example having 2, 3 and 5 channels, may be reasonably produced.
  • FIG. 4 represents the rotary head device of this invention in the state of being turned by 90 degrees to its horizontal posture.
  • the length in the longitudinal direction of the shaft 22 of the herringbone pattern of grooves 26A closest to the upper cylinder 29 end of the rotary shaft 22 is made greater than the length of the herringbone pattern of grooves 26B on the motor side, which is smaller. Accordingly, even when the sleeve 21A of the lower cylinder is bent downward, because of the high oil film rigidity on groove 26A and the low oil film rigidity on 26B, the rotary shaft will not be in parallel with the sleeve, but the tilting of this sleeve 21A is cancelled, so that it turns while remaining parallel to the lower cylinder.
  • a rotary head device using a fluid bearing which is compact and excellent in portability is obtained by making a larger pattern of herringbone grooves on the upper cylinder end, and a smaller pattern of herringbone grooves on the motor end of a rotary shaft, and by providing pairs of rotary side and stationary side cylindrical transformers mounted coaxially with respect to the rotary shaft and to each other.

Landscapes

  • Sliding-Contact Bearings (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
US06/619,147 1982-09-30 1983-09-30 Rotary head device with fluid bearing Expired - Lifetime US4706144A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP57-172723 1982-09-30
JP57172723A JPS5963024A (ja) 1982-09-30 1982-09-30 流体軸受シリンダ−装置

Publications (1)

Publication Number Publication Date
US4706144A true US4706144A (en) 1987-11-10

Family

ID=15947131

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/619,147 Expired - Lifetime US4706144A (en) 1982-09-30 1983-09-30 Rotary head device with fluid bearing

Country Status (5)

Country Link
US (1) US4706144A (enrdf_load_stackoverflow)
EP (1) EP0128221B1 (enrdf_load_stackoverflow)
JP (1) JPS5963024A (enrdf_load_stackoverflow)
DE (1) DE3382420D1 (enrdf_load_stackoverflow)
WO (1) WO1984001464A1 (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4961122A (en) * 1987-05-11 1990-10-02 Hitachi, Ltd. Hydrodynamic grooved bearing device
US5022492A (en) * 1988-04-20 1991-06-11 Matsushita Electric Industrial Co., Ltd. Fluid-bearing apparatus
DE4104264A1 (de) * 1991-02-13 1992-08-20 Broadcast Television Syst Abtasteinrichtung fuer ein magnetbandgeraet
US5299085A (en) * 1991-04-05 1994-03-29 Sony Corporation Compact rotating head assembly
US5381285A (en) * 1991-07-05 1995-01-10 U.S. Philips Corporation Bearing arrangement, device with rotatable disc, and magnetic-tape apparatus
US5453892A (en) * 1990-06-11 1995-09-26 Sony Corporation Rotary magnetic head drum with fluid bearing and with head chips mounted together in parallel
US5666245A (en) * 1995-02-15 1997-09-09 Daewoo Electronics Co., Ltd. Head drum assembly provided with an amplifier therein
US5793561A (en) * 1994-10-14 1998-08-11 Canon Kabushiki Kaisha Rotary drum assembly having dynamic-pressure generating mechanism between rotary shaft and bearing
RU2137217C1 (ru) * 1995-05-22 1999-09-10 Интернэшнл Бизнес Машинз Корпорейшн Поворотный подшипник
USRE38373E1 (en) 1997-09-19 2003-12-30 Capstone Turbine Corporation Compliant foil fluid film thrust bearing with a tilting pad underspring

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60185312U (ja) * 1984-05-21 1985-12-09 赤井電機株式会社 磁気記録再生装置におけるロ−タリ−トランス構造
KR950003210B1 (ko) * 1987-08-31 1995-04-04 주식회사 금성사 브이씨알의 회전 헤드 드럼장치
JPH03268272A (ja) * 1990-03-16 1991-11-28 Matsushita Electric Ind Co Ltd 磁気記録再生装置
US7099457B2 (en) * 2001-07-17 2006-08-29 Comverse Ltd. Personal ring tone message indicator
US7366295B2 (en) * 2003-08-14 2008-04-29 John David Patton Telephone signal generator and methods and devices using the same
JP2009156333A (ja) * 2007-12-26 2009-07-16 Ihi Corp 回転機械の軸受装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3494674A (en) * 1967-03-31 1970-02-10 Philips Corp Hydrodynamic bearing for axial and radial loads
US3763327A (en) * 1970-08-05 1973-10-02 Fernseh Gmbh Magnetic head wheel rotor and transformer assembly with anti-rotation locking means
US4031558A (en) * 1974-08-27 1977-06-21 Sony Corporation Head drum assembly with electrical noise shield
US4080639A (en) * 1975-05-22 1978-03-21 Robert Bosch Gmbh Adjustable assembly elements for a scanning device for magnetic tape instruments
US4099210A (en) * 1976-10-04 1978-07-04 Dolby Dale P Rotating transducing head assembly
US4197565A (en) * 1977-08-26 1980-04-08 Sony Corporation System for reproducing a video signal recorded in parallel track sections on a recording medium
JPS55163320A (en) * 1979-06-05 1980-12-19 Matsushita Electric Ind Co Ltd Rotational device
US4408239A (en) * 1980-06-12 1983-10-04 Canon Kabushiki Kaisha Rotary magnetic head drum assembly for magnetically recording and/or reproducing device

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL282966A (enrdf_load_stackoverflow) * 1962-09-06
JPS433767Y1 (enrdf_load_stackoverflow) * 1966-05-02 1968-02-17
JPS5923376Y2 (ja) * 1976-02-27 1984-07-12 株式会社共和電業 回転トランス
JPS5945844B2 (ja) * 1979-07-26 1984-11-09 松下電器産業株式会社 回転装置
JPS5620830A (en) * 1979-07-26 1981-02-26 Matsushita Electric Ind Co Ltd Rotation transmitting device
JPS5945845B2 (ja) * 1980-12-09 1984-11-09 松下電器産業株式会社 回転装置
US4487514A (en) * 1981-09-29 1984-12-11 Tokyo Shibaura Denki Kabushiki Kaisha Motor
DE3463450D1 (en) * 1983-06-01 1987-06-11 Nill W Metallbau Outlet for a barrage or sedimentation tank

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3494674A (en) * 1967-03-31 1970-02-10 Philips Corp Hydrodynamic bearing for axial and radial loads
US3763327A (en) * 1970-08-05 1973-10-02 Fernseh Gmbh Magnetic head wheel rotor and transformer assembly with anti-rotation locking means
US4031558A (en) * 1974-08-27 1977-06-21 Sony Corporation Head drum assembly with electrical noise shield
US4080639A (en) * 1975-05-22 1978-03-21 Robert Bosch Gmbh Adjustable assembly elements for a scanning device for magnetic tape instruments
US4099210A (en) * 1976-10-04 1978-07-04 Dolby Dale P Rotating transducing head assembly
US4197565A (en) * 1977-08-26 1980-04-08 Sony Corporation System for reproducing a video signal recorded in parallel track sections on a recording medium
JPS55163320A (en) * 1979-06-05 1980-12-19 Matsushita Electric Ind Co Ltd Rotational device
US4408239A (en) * 1980-06-12 1983-10-04 Canon Kabushiki Kaisha Rotary magnetic head drum assembly for magnetically recording and/or reproducing device

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4961122A (en) * 1987-05-11 1990-10-02 Hitachi, Ltd. Hydrodynamic grooved bearing device
US5022492A (en) * 1988-04-20 1991-06-11 Matsushita Electric Industrial Co., Ltd. Fluid-bearing apparatus
US5453892A (en) * 1990-06-11 1995-09-26 Sony Corporation Rotary magnetic head drum with fluid bearing and with head chips mounted together in parallel
DE4104264A1 (de) * 1991-02-13 1992-08-20 Broadcast Television Syst Abtasteinrichtung fuer ein magnetbandgeraet
US5278715A (en) * 1991-02-13 1994-01-11 Bts Broadcast Television Systems Gmbh Scanning device for magnetic tape with special disposition of rotary transformers for recording and playback magnetic heads
US5299085A (en) * 1991-04-05 1994-03-29 Sony Corporation Compact rotating head assembly
US5381285A (en) * 1991-07-05 1995-01-10 U.S. Philips Corporation Bearing arrangement, device with rotatable disc, and magnetic-tape apparatus
US5793561A (en) * 1994-10-14 1998-08-11 Canon Kabushiki Kaisha Rotary drum assembly having dynamic-pressure generating mechanism between rotary shaft and bearing
US5666245A (en) * 1995-02-15 1997-09-09 Daewoo Electronics Co., Ltd. Head drum assembly provided with an amplifier therein
RU2137217C1 (ru) * 1995-05-22 1999-09-10 Интернэшнл Бизнес Машинз Корпорейшн Поворотный подшипник
USRE38373E1 (en) 1997-09-19 2003-12-30 Capstone Turbine Corporation Compliant foil fluid film thrust bearing with a tilting pad underspring

Also Published As

Publication number Publication date
EP0128221B1 (en) 1991-09-25
JPS5963024A (ja) 1984-04-10
EP0128221A4 (en) 1986-01-28
WO1984001464A1 (en) 1984-04-12
DE3382420D1 (de) 1991-10-31
EP0128221A1 (en) 1984-12-19
JPS6321244B2 (enrdf_load_stackoverflow) 1988-05-06

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